AMV Reverse Transcriptase XL synthesizes complementary full-length cDNA from single-stranded RNA, DNA, or RNA-DNA hybrid templates. The enzyme requires a primer to initiate synthesis and Mg2+ or Mn2+ for activity. AMV Reverse Transcriptase XL is positive for 5→3' ribonuclease H activity and can be used for a number of applications, including reverse transcription. AMV Reverse Transcriptase XL is highly purified, free of extraneous nucleases and is qualified for use in full-length cDNA synthesis and reverse transcription using RNA templates that are up to 10 kb in length. It can be used over a temperature range of 37–55°C, but maximal yield of full-length cDNA products is achieved between 41–44°C.